Electromagnetic modeling of stress corrosion cracking for depth sizing based on eddy current testing

This study discusses the electromagnetic modeling of stress corrosion cracking (SCC) model to improve accuracy of depth sizing of SCC with eddy current testing (ECT). For the purpose, the factors that influence eddy current (EC) signals of SCC are evaluated. In this study, the crack morphology and oxide fillings of SCC are focused on as influencing factors. As a first step, SCC introduced at room temperature and fatigue cracks with oxide fillings are evaluated. To discuss the EC signals of SCC, SCC are artificially introduced and their EC signals are obtained. The EC signals of SCC are much smaller than that of fatigue cracks. To discuss the influence of oxides in fatigue cracks on EC signals before SCC measurement, oxides are systematically filled in fatigue cracks by thermal treatment, and their EC signals are acquired. The EC signals change depending on the presence and type of filling oxides. Numerical simulations are conducted to discuss the electromagnetic modeling of cracks with oxide fillings. It is confirmed that conductive oxides in cracks as well as martensitic phase layer influence the EC signals. (author)